Call box register circuit



July 25, 1%3. A. A. CLOKEY CALL BOX REGISTER CIRCUIT Filed July 17, 1930INVENTOR ALLISON A. CLOKEY ATTORNEY come. ever, is toprovidesimplerarrangements tomg descriptlon:

Patented July 25,1933

* UNITED STATES,

PATENT err-rin f:

ALLISON A. .OLOKEY, or RUTHERFORD, NEW JERSEY, A ssIGnons'rom'rnnnnrroivnn COMJVIUNICATIONS LABORATORIES, INC., .NEW YORK vApplication filed. 1.111; 17,

This invention relates to calllbox register circuits, such as messengercall systems, fire. alarm systems and watch'mens signalling systems. Ithas particular reference to the line relay and other means whereby thecode register may be; caused to function, even under abnormal conditionsof the circuit.

Systems which include" a number of code signalling stations in series'onone circuit. are frequently subject to line trouble such as an opencircuit, a ground, or'a combina-, tion of the two. Means are known inthe art whereby such line troubles can be over- The object of thisinvention, howrender the'register operative under abnor mal as well asnormal conditions, and particularly to employ only one' relay 'in theline circuit rather than twoas heretofore.

In carrying out this invention it is preferableto use call boxesequipped with code} impulsing wheels and to provide a contact device inassociation with the impulsing wheels such that in makinga call not onlyis the line momentarily grounded but also opened for each pulse of thesignal; This signalling means in combination with the novelarrangement'of the receiving relay and its associated switchingmechanism re ders the circuit'operative from a call box located oneither side of an accidentally grounded point or break in the line, or acombination of the two. 1 i I In the drawing accompanying the follow.Fig. 1 shows diagrammatically the call box' circuit and thearrangements at the register station.

Fig. 2 shows a typical detail of the code wheels within a call box.

Fig. 3 shows anarrangement ofthe line relay and its connectionsalternative to the portion of Fi 1 comprehended in the broken line oneosur'e; c

vIn Fig. 1 four loop circuits, A, B, G and D illustrate respectivelyeach of fourline conditions which may possibly occur on any one circuit.The call boxes, 4," 5, 6 and 7 are placed at any desired points along.the line. The two ends of the loop-"T and R,

OF. NEW .YORK,.'N.' Y., A CORPORATION OF .cALL' Box REGISTER cmcnir1930, Serial No. 468,606.

should be regarded as' terminating at the register station where theyare connected respectively with ther'eceiving relay circuit as at T andR. v v c Loop .A shows a normally closed circuit over which signalsmaybe transmittedjfrom any call box by 'openingthe circuit for each codeimpulse; Loop B shows a break or opencircuit condition as at Loop Cshows an abnormal ground as at F. Loop D sh'owsat Gr an Y ground. a c cThe receiving apparatus comprises a line relay 8, akey, switch havingthree positions designated 1, 2 and 3' respectively, abo e signal.register 9 and sources of potential 10 and 11, the voltages of which maybeisuitably cut down'for.practicalpurposes by the use of the resistances12 and'13; Inthe' call box, Fig.2, the. code wheel 14: isrecessed as at16 to provide a series of open pulses when the wheel rotates in aclock-wise direction asindicated. This particular code wheel has notchesarranged to send the signal c2 3+1. Associated with it is the codewheel'15 on whichare teeth 17 arranged in the same code combin ation'jas[the notches 16 on wheel'-11.""The contact spring 18' bearing againstcode wheel. 14

normally completes the circuitthrough the box in the directionR-T of theloop.-] The contact spring 19 bearing against the'teeth 17 of code wheel15 momentarily puts ground on the loop immediately prior to opening itfor thefsignalling pulses. I

The operation lows: 1

open circuit andat H a of the system is as fol} The normally closedcircuit condition 7 will first; be assumed as represented'by loop A; Theproper position of the key switch for this condition is with itscontact-spring operating lever 1n posltion 1 as shown. Prior to sendinga signal, current flows from battery 11 throughiresistance 13, con-ftacts 20 and 21, loop A in the direction lay 8 and contacts 24-and 25130 ground."

ever, close any circuit through the regiswill send out a series of openpulses corresponding to the code number characteristic of thatparticular box. These open pulses cause relay 8 to release, thus closingthe register circuit for each open pulse and" tape Whichwfll beunderstood tobe issued by the register 9.

The register circuit may" be tracedjfron'rl battery through resistance12, contact springs 28 and 27 ofthe"key-svviteh,-backcontact andarmature33 of, relay 8 and thence to the register, 9 Whichis grounded.YIf the line is" accidentally. opened; as shown at E on loop"B a'continuous mark will thenibe recorded. by the. register 9 7 owing to therelease'io relay '8. To over- V circuit is grounded.

position 3. 25v

come this" condition thet operator at the register. station places theswitch key in The operation of the enema B win that fbefas follows:- Nocurrent fiowstffroni; bat

tery 11 ,eXceptWhen sending a signal and when the teeth 1710f the codeWheel '15 are traversed 5 by the grounded contact 19.

The circuit then established for each signal ling pulse-may be tracediroin battery ll through springs 26and 24 of the key switch to theconnecting "point 31 between the two windings of.relay..8, throughonefof said windings or the other according to thewlo cation of the.break E withrespectl to the box; from which the call is beingfniadeithence. the current 'ffiows either through loop terminalR tocallboX 5 orthrough ter}: minal T to one of the boxes :4, thecalling Belay8,'thelfefbre, pulls up iits 33' for each. signalling. pulse. Theregister 9 now.re sponds .to the closure of the a'rina ture; 33 andfront contact .34 of relay 8,: sincethekey-switch contacts 28 and 29 areclosed together. v V p F or "the condition of ground as indicated at Fon loop C,- the coils of reh yf8 have to be. differentially connected asshown and these windings have equal resistance and anequal number ofturns.v

' To meet this .lcondition the key-snitch is placed, in position?) and,current flows from" battery. 11. through resistance 13, contacts 26 and24,. through both Windings'oir relay 8,111 opposition (causingthef relayto bet ile-energized) .and thence through both legs of the loop circuitC to ground F; In pass? ing to leg It; current flowsfrom relay coil3l,32, through key-switch contacts 22 and Assuming noW that (me or atseem a on loop 0 makes a call, then'thecode signal box in any caseb'eingtheflpoint Where the will be transmitted in the form of openimpulses on the leg T of the loop C. This willtle-enei'gize coil 30-31of relay 8, while I p v V other side of the ground? should call, thenrecording the code number on the register the signals would be received"over the leg R of loop C and relayS Would operate from the continuanceof current flow in. coil "30- 3l ,*-;While coi1"31-32 dehnergized ateach slgnalhng pulse.

"The fourth condition Which is provided rel-1st breaklG and aground 'H,as shown in. loop DQ', This fault iscorreetedby placing the key switch nposit on 2,. whercat the operatioiifof the circuit is as follows Beforezrcall is" made, current will now:

through stations 4 of this loop to ground.

Tlhe open circuit at 'fGf fde en'ergizes the opposing winding 31 32andhence the armature. 33 1S, normally pulled'up. Slnce con-.

tacts 28and 29fia're open for position 2 of the key-switch; no currentcan pass to: the 9 while therelay 8 1'61113111561101 register glzed.

otfthefstations'l on loop D; heopen iin pulses .will de energize coil 3130, of relay 8, causing its armature 33 to makew th its backcontactflfi,- thereby operating the reg ister 9. Iffa callis initiatedfrom boX. 7 which is on theR-side of the break G, then the groundimpulses resulting from the rotation of code; wheel 15 will causecur-rent to energize coi-l 31.32 in opposition to thepre v ouslyenergizedfeoil 81 30. Each impulse gwill, therefore; cause the relay torelease,

operating the register-. 9 whenns armature makes-With the backcontact.

arrangement of the line relay and key switch will be explained,v n1tlllS-lllbQtlh ment of the invention itis not necessary for the relaywinding to be tapped at the middle, but instead, two equal rcsistOrsSSand 89 are provided and the r connections through the key-switch aresuch that they; niay be bridged across betweenthe-terminals of the relaywinding,.while the inidpointbetween the two resistorsisj connected tothe battery 11- through the resistance 13.

' Relay 41 operates in the following manner Assume n w that a call ismade from one ';Refer;1'i1 1g now to Fig.3,an alternative under the fourconditions indicated by the 2 loop circuitsA, B, O and D re speetivelyzThenormally closed circuit represented by loop isproyided Whenthekeyswitch is i set iniposition 1. Current flows from battery llthroughresistances 13 and 39, loop terminals Rif -R, thence through thecall boxes 4 to loop terminals T whichfare and 29 as in Fig.1,-and'it-.will be recalled that these springs supply current frombattery 10 eitherto thefront contact 34 or to the back contact 35,according as it is required that the register shall record signals whenthe line relay energizes or de-energizes.

In signalling as onloop A,.-with switch-key lay 4 1 releases. 1 I

,To meet the cond'tions that may exist either on loop B ,}o'1 loop. :C,thekeyswitch is placed in position 3. If the circuit is accidentallyopened as YatE then the potential at the two terminals of the relaywinding is normally equalized by the equal resistances 38 and 39, and nocurrent will flow until a signal is initiated at one of the call boxes,say box 5. Thereat the grounding of the loop on the side ofthe terminalR,

in position 1,'--the register operateswhen rewhen the code wheel teeth17 are traversed of loop B to call box 5 where the code signal respondequally well to a call originated at one of the stations 4 on loop B,but current will flow through coil 40 in the opposite 'di rection tothat caused by call from box 5.

is originated. Current will also be bypassed through resistance 39,butnevertheless the drop of potential through coil 40 will besuflicientto operaterelay 41in response to the signals. The relay .41 will If thecircuit is accidentally grounded as at F. on loop C, current willnormally flow about equally. through the two legs R and T of the loop C.Hence the drop of potential throughrelay winding 40 will be negligibleuntil a call is made. When a-call originatesat one of the boxes 4, the,opening of the circuit by means of thecode wheel 14 at that boxwillremove ground from leg T of loop C- and hence the potential drop inresistance 38 will be diminished and a cur:

rent flow through coil 40 will be setup, ex-

tending through leg R to the groundedpoint.

balanced potential across .its winding 40 when each signal ceases.

It is obvious that a signal originating 'at one of the call boxes 6 onloop C would like- J wise actuate relay 41 except that the drop ofpotential through its winding 40 "would be in the opposite direction tothat just described. The fourth condition of an: open, G, and

ground, H, as represented by loop D is taken care :of by placing thekey-switch in position 2. Current normally flows from batteryill-through resistances 136116.39, contacts 46 and-44, relay winding 40,and terminals T-T to the grounded point H, thus energizing the-relay.Current is also by-passed through resistance 38. but this .has no effectuntil a call is originated, say at one of the boxes 4. The opening ofthe circuit on the T side of loop D causes the potential to be equalizedacross the winding 40 so that the relay 41 is deenergized in response tothe breaking ofthe circuit for each signal from thecalling box '4.

Thepotentialacross the winding 40 is also equalized but with currentflowing when signals are transmitted from call box-7. In this case thecode Wheel 15 at call box 7 putsground 'on the B" side of loop D, so

that current flows equally through, resistance 39 tothe groundedcontact'19 and through resistance 38 to the accidental ground H. V

The relay 41 at this time de-energizes in response to each signal.

The operation of the register 9 in each of the four cases described inreference to Fig. 3 will be understood from the description applying toFig. 1. 1 i

It will likewise be understood from an examination of the drawing andthe accompanying description that whenever the switch key is positionedto take care of one condition of the loop circuit, as abreak condition,and another condition of the loop then occurs, as a combination breakand groundrcondition, the register 9 is arranged to mark continuously inresponse to the changed condition until the key has been properlypositioned.

What is claimed is: I I

1. Ina signalling-system, the combination of a loop interconnecting aplurality of calling devices each provided with means for grounding andthen opening a point on said loop, a relay and a register controlled tothe release of said relay, said switching,

means; being operable when an accidental break occurs in said loop toconnect each leg Thus the relay .will be energized in reof said loopthrough equal resistances to. a

grounded source of" potential, to condition said, register to respond tothe operation of. said relay, and to connectsaid relay 1n shunt acrosssaid loop whereby sald relay is operated upon each grounding of the legon one ans 1 f the. operation of any calling-device therein,- and.condltloning said register to :respond to the release of s'aidarelay,said switching means being operable *when an accidental grounding ofboth legs of said loop occurs to connect each legthronghequalresistances to agrounded source of potential', tocondi tionsaid register to respond'to theso'peration,

of said relay, and to connect-said relay in shunt across saidrloopwhereby said relay is operated .upon each opening of the leg ,on oneside of said'ground by the operation of any calling device includedinsaid leg.

c In a signalling systennthe combination of a loop interconnectingaplurality of call- L ing :deviceseach provided'with means for groundingand then opening a point on said loop, a relay and a 'rcgistercontrolledthere by, and switching means normally connecting said relay:and'saidloop in a closed series circuit, whereby said'relay isde-energizableuponeach opening of said loop by the operation of any.calling device therein,

( and conditioning said register to respond to the release of saidrelay, said switching means being operable when'a break'in saidloop'occurs and the leg on one side of the break is grounded to connecteach leg of said loop through equal resistances to a grounded source :ofpotential, to condition said register to respondto the de-energizationof said relay, and to connect said relayin shunt across said loopwhereby said relay is de-energizedfupon each it grounding of theungrounded le'g by the; operation of-any calling device therein and isalso Lie-energized upon each opening of thergrounded' leg by theoperation ofany calling device in said i) i [ALLISON A. oLoKEY.

